Method of decolorizing oils



R. c. OSTERSTROM METHOD OF DECOLORIZING OILS Filed June 18, 1928 June 23, 1931.

Patented June 23, 193i UNITED STATES PATENT OFFICE RUDOLPH C. OSTERSTBOM, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE PURE OIL COM- PANY, OF CHIGAGOyILLHQ'OIS, A CORPORATION OF OHIO METHOD OF DECOLOIB-IZING OILS Application medium: is,

This invention relates toan improved process for effecting the decolorization and purifying of hydrocarbon distillates and it is a particular object thereof to provide an improved process in which the oil under treat ment is brought into intimate contact with a refining agent while the latter is in a finely divided form and wherein improved-contact between the refining agent and the oil is provided by passing the resulting mixture of the oil and the contact material or refining agent through a heater in which the oil is heated to relatively high temperatures but maintained in the liquid phase by the employin'ent of pressures preventing the evolution of vapors. i

It is another object of the invention to pass the oil and refining agent or contact material from the heater through a contact zone in, which zone the moisture is maintained under reduced pressures so as to permit of the liberation of vapor for the purpose of breaking up the contact material and to provide greater surface contact between the refining agent and the oils under treatment. Further, it is a purpose of the invention to form the contact or reaction zone in such manner as to secure a time factor admitting of a thorough and intimate engagement of the oil vapor or liquid oils with the contact material and finally to provide means for fractionally separating the polymerized oil and contact materials from the purified oil vapors so that the latter may be separately condensed and collected. i

It is a further object of the invention to provide an improved process for refining oils in which the refining agent is thoroughly impregnated with the oils under treatment,

wherein refining properties of said agent are utilized to the maximum extent.

A still further object of theinvention resides in the provision of a continuously r operating system wherein the oil to be treated is introduced into one end of said system and after treatment is continuously removed from the other end thereof, and wherein the oil under treatment in the system is subjected to fluctuating pressure and temperature conditions so regulated as to procure maximum 1928. Serial No. 286,103.

contact between the oil and the refining agent I to the end of positively and efficiently removinlg updesirable compounds from the treated oi t disclosed herein and embraced by the invention described is not only applicable to the treatment of petroleum hydrocarbon oils, but may also be employed in treating various other oils such as, for example, vegetable oils, animal oils and other liquids capable of being treated in accordance with this invention.

The objects of the invention and one manner of giving it practical application may be best appreciated from the following description of .an illustrative embodiment thereof, taken in connection with the appended claims and the accompanying drawing in which: The figure is a diagrammatic view showing the general arrangement of apparatus suitable for use in practicing the invention, parts being broken away and disclosed in section to set forth the interior structure. The figure is provided with legends and other features adapting it to serve incidentally as a flow sheet.

Referringto the drawing, the numeral 1 indicates a storage tank for the liquid to be treated. This liquid is preferably a distillate obtained from oil refining processes and it may have been previously acid treated or it maybe a distillate obtained directly from a still or converter. Connected to the tank 1 is a supply pipe 2 which leads from the discharge side of the tank 1 and is provided with a regulating valve 3, ordinarily manually operated. Frpm the valve 3 a pipe 4 communicates with a pump 5 of any suitable type, either rotary or reciprocatory. The outlet from the pump 5 is connected to a mixer 6, which leads to the bank of coils 7 in the heater or contactor 8. The mixer 6 may in many instances be omitted.

A clay hopper is indicated by the numeral 9 and has the outlet 10 thereof controlled by the valve 11. The outlet from the clay hopper communicates with the clay feeder 12, which in this instance takes the form of a tube 13, provided internally with a screw conveyor 14. This conveyor is preferably driven by means of a variable speed motor ,15 or by other is to be undcrstoodthat the method a equivalent apparatus. The clay feeder 12 communicates at its outlet end with the ipe 4 which carries the oil under treatment f fom the storage tank .1, the clay feeder 12 being preferably arranged in angular relationship with the pipe 4. Again, said feeder will have a downward slant from'the outlet 10 to the pipe 4, whereby the effect of gravity may be employed in treating clay to the oil passing through the pipe 4. The term clay is used in its generic sense in this specification and is intended to refer generally to refining agents, such for example as fullers earth, charcoal, various types of clay, some varieties of light and porous magnesium silicate, ani mal and vegetable chars, diatomaceous earth, with and without a coat of carbon, certain clays or clay-like materials which have been treated with acid, and in general such solid materials as may be reduced to a fine powder after intermixture with the oil and which when so intermixed show the property of withdrawing coloring matter or other un-.

desirable impurities from the oil. Among such other impurities may be mentioned the gum forming compounds of the oil so as to provide a treated stock suitable for use as motor fuel. Other treating or refining agents, of course, ma 1 be used which have the function of bleaching or decolorizing the fuel under treatment.

The contractor or heater 8, for illustration, has been shown as being provided with a burner 16 or any other suitable device may be used for imparting fire gases to the coil 7 in the heater. It is within the range of the invention to employ excessive heat remaining in the furnace gases, following their release from the heater 8, for the purpose of preheating the oil prior to its entrance into the heater, and other heat economies may, of course, be provided which are matters of standard practice and to not enter directly into the features of the present invention. The outlet end of the bank of coils 7 is provided with a pressure relief valve 18, which may be either of the automatic or manually operated type and capable of being so controlled as to govern the pressures which obtain within the tubes comprising the coil bank 7.

The oil and the refining agent are preferably continuously supplied through the pipe 1 and the clay feeder 12, respectively, said oil and refining agent being forced by the pump and as a mixture into the coil 7 of the heater 8, the oil and refining agent being intimately mixed either in the pump 5 or in the mixer 6. The pressure maintained within the coil bank 7 will vary to conform to optimum operating conditions. It has been found-that some oils respond to treatment at temperatures as low as 150 F.

and at pressures as low as 40 pounds above atmospheric. Other oils will not respond until they are treated to temperatures as high as 500 F., and with pressures varying from 40 to 750 pounds per square inch, as will be readily understood by those skilled in the art. It will be understood that in order to secure the best results it is necessary to vary the temperatures and pressures with changes in the oil under treatment and also with changes in thenature of the refining agent. For example, different temperature and pressure conditions will have 'to be used during the treatment of a vegetable oil than those employed during the treatment of a petroleum oil. By maintaining the oils in the heater under super-atmos pheric pressures the oils remain in a liquid state and the evolution of vapor is substantially precluded. This enables the oil to penetrate the pores of the contact or catalytic material used even though the latter may be in a finely divided form when originally introduced into the system. The operation permits the oil to thoroughly saturate the pores of the clay. The mixture of oil and adsorbent should not be heated, however, to above a cracking temperature, norshould the temperature and pressure conditions to which the mixture of oil and adsorbent is subjected be of such order as to cause cracking. It is to be understood, however, that the action of the adsorbent upon the oil may tend to form a minor quantity of lighter components, but such formation is generally not termed cracking. g

Following this operation the oil 18 passed from the heater by way of the pressure reducing valve 18 into av pipe line 19. The pressure reducing ,valve provides for much lower pressures in the pipe line 19 than in the coil 7, since pressures in excess of 200 pounds per square inch seldom obtain in the pipe line 19 and the, reaction or contact chamber 20 connected therewith, the pipe line 19 and the chambers 20 constitute what may be termed the entire contact zone. Due to the fact that the pressureon the oil under treatment is suddenly dropped to a very marked extent when the oil leaves the heater 8 and enters the pipe line 19, it follows that expansion of the evolved oil vapors results in breaking down the clay particles or other contact material used, thereby exposing greater surface for contact with the oil vapors, and to aid to increase the rate and amount of polymerization of the undesirable compounds. One or more of the contact vessels 20 may be utilized, the size and number depending on the amount of oil to be treated per unit of time and the amount of the refining agent required. The contact chambers rovided in the vessels 20 are formed to indlude conical tops and bottoms, so that the mixture of vapors and fullers earth will enter at the bottom of each chamber and pass out at the top through relatively restricted orfices. It is in these chambers that the maximum treating effect or action of the fullers earth on the oil is obtained. The natural tendency of the clay is to settle or fall and the force of the vapors passing therethrough give a maximum amount of contact and treating efliciency, it being desirable to construct the chambers of such size that the ratio of fullers earth to gasoline vapors is much greater in these chambers than in the pipe line 19 leading to the chambers. These treating chambers are also built or made of such size and number that the desired time element will be obtained, as the polymerization of the undesirable color and gum forming compounds, such as diolefines, is a reaction requiring time for execution. It has been found necessary in some cases to hold the time of contact as high as sixty minutes, while in other cases complete removal of the undesirable compounds is obtained in five minutes or less. The polymerization taking place in the contact chambers is an exothermal reaction, the rise in temperature in some cases being 235 F. This heat of reaction prevents any possibility of cooling of the oil vapors in the contact chambers, and, therefore, insures complete vapor phase treatment. v

After leaving the contact chambers 20, the mixture of oil vapor and fullers earth passes through a pipe line 21 provided with a pressure reducing valve 22 of the type indicated at 18, and by the pipe line 21 theoil vapors are introduced into a se arator 23 It will be understood that by t e provision of the reducing valve 22 ordinary atmospheric pressures may be employed in the separator. This separator is in the form of an evaporator or tower, wherein the clay is allowed to fall to the bottom thereof and the vapors pass out overhead from. the top. It is preferable to regulate the temperature of the outlet of the separator, such. as by a reflux coil 24, to maintain such outlet temperatures constant, permitting the oil vapors to be fractioned closely within desired boilin point ranges. I Suitable means can be provi ed'for removing the spent clay from the bottom of the separator, such as a manhead 25, which may be placed on one side of the separator and in connection therewith there may beemployed a conveyor screw 26 arranged in a screen 27 provided in the bottom of the separator, the

screen serving to continuously remove the spent clay, while the liquid oil may flow through the screen 27 and escape from the bottom of the separator by a valve controlled outlet 28 which leads to a collector 29.-

While there has-been specifically described a particular typaof contact vessel which may be used in carrying out the invention, nevertheless it will be understood that other types of vessels may also be utilized. In fact, any of the ordinary types of orifice mixers may be used.

'The polymerized fraction that has been formed in the contact vessels, and which has a higher boiling range than the desired final product, condenses and becomes a liquid at the temperature which: is maintained in the separator 23, and this condensate drops to the bottom of the separator with the clay. Although most of the clay is retained on. the screen 27, a certainproportion of very finely divided clay passes through the screen with the polymerized components, the clay-polymerized hydrocarbon mixture being allowed to drop out of the bottom of the separator by way of the outlet 28, the extent of the opening of which determines the rapidity of the removal of the liquid clay mixture. Passing this outletthe mixture is further cooled by a coil situated in the collector 29. This collector is a tank with a pitched bottom almost completely filled with water. On being released into this mixture the clay and heavy tarry matter settle, to the bottom, while the lighter fractions, of the oil entrained with the clay rise to the top of the water, where such lighter fractions can be continuously removed by overflowing through the pipe line into storage, or may 1pc pumped from the top of the water surace.

The lighter vapors, released from the claypolymer fraction passes upwardly through the baflies 30 in the separator and after passing the reflux coil leaves the separator by an overhead line 31. .This line may pass through a condenser 32, in which the vapors are reduced to liquid form by a decrease in their temperature and then finally delivered to a storage tank 33. I V

The finished gasolines from the above process are of good stable color, odor and of low gum content, but in many cases in order to get a finished product, sweet tothe doctor test, this has been accomplished by the addition of a small amountof lead oxide to the fullers earth in the hopper 9. The advantages of the above system are manifold. First, the system allows theuse of very finely ground fullers earth, which has the advantage of greater surface area over the coarser grades of clay which are used in percolation methods, the polymerizing or decolorizing action of the earth being dependent upon this surface area. Due to the phasean' increased efliciency is obtained oyer treating in the liquid phase, which is also a factor in reducing the amount of treating agent required. In other words, the above system allows the use of a clay in such form that its greatest efficiency is obtained, and at the same time applying the clay on the oil which is in such a condition, as regards temperature and pressure, that it is most easily affected by thetreating agent. First, it is desired to thoroughly impregnate the pores of the clay with the oil while the latter is in a liquid state, and then to procure greater intimacy of contact by breaking up the finely divided clay to an even greater extent and while the oil is in the vapor phase. Other systems heretofore proposed for accomplishing similar results purpose employing either the liquid phase method or the vapor phase method. It is the intention of the present invention to combine both of these methods into a single system, wherein the advantageous features of both methods are utilized to produce an even more eflicient system.

What is claimed is: i Y

1. The method of decolorizing and purifying petroleum oils with adsorbent clay, which comprises heating a mixture consisting solely of an oil to be decolorized and an adsorbent clay in a finely divided form to a temperature above that at which the oil under treatment vaporizes but below a cracking temperature, preventing the evolution of oil vapor from such mixture by the application thereof while the latter is under heat treatment of super-atmospheric pressures suflicient to maintain the oil in the liquid phase and to cause the oil to thoroughly penetrate the clay refining agent, reducing the pressure On the oil and clay mixture immediately following the heating operation for the purpose of releasing vapors causing the particles of adsorbent clay to becomesuspended inthe vapors, maintaining the oil vapors and clay at such reduced pressures for a period of time sufiicient to insure the desired contact between the adsorbent clay and the oil, and then further reducing the pressure on the oil vapors to admit ofthe separation of the claypolynier fraction of the oil from the light or purified fraction.

2. The continuous method of purifying or decolorizing petroleum oils with adsorbents which comprises: continuously heating a confined flow-stream composed solely of an .oil to be decolorized and an adsorbent having properties of fullers earth to a tempera ture above the vaporization point of the oil but below a cracking temperature while applying 'pressure to the stream to prevent the evolution of oil vapor, removing at least partially the pressure on said stream to cause the evolution of oil vapor, continuously passing such oil vapor in a flowing stream through a contact zone wherein the vapor is brought into intimate and extended cont-act with the adsorbent while the oil is in the vapor phase, and then further reducing the pressure on the flowing 'oil vapor stream to admit of the separation of the lighter and purified fractions from the heavier and undesired fractions.

' vaporization point of the oil under treatment but below a cracking temperature while maintaining the oil in the liquid phase by placing the same under super-atmospheric pressures sufficiently high to prevent the evolution of oil vapor, reducing the pressure on the flow-stream at the outlet end of said tube bank to permit of the formation of oil vapor, continuously circulating such oil vapor and suspended adsorbent in a turbulent, agitated condition through a contact zone, further reducing the pressure on said flow-stream following the release of the latter from said contact zone, and in then fractionally separating the desired and undesired constituents of the flow-stream.

4. In a method of purifying and decolorizing petroleum oils, the steps of heating a mixture of petroleum oil and a finely divided adsorbent clay to a temperature above that at which the oil under treatment vaporizes but below a cracking temperature, preventing the evolution of oil vapors from said mixture by the application of super-atmospheric pressures thereto while said mixture is under heat treatment to maintain the oil in the liquid phase and to cause the oil to thoroughly penetrate the adsorbent clay, reducing the pressure on the mixture while said mixture is substantially at a temperature above that at which the oil vaporizes, for the purpose of.

releasing vapors and maintaining the oil .vapors and finely divided adsorbent clay at such reduced pressure for a-period of time sufficient to insure the desired contact between the adsorbent clay and the oil vapors.

5. The continuous method of purifying petroleum oils with adsorbents, comprising continuously heating aflow stream of oil to be treated anda finely divided adsorbent clay to a temperature above that at which the oil under treatment vaporizes but below thatat' which cracking takes place, preventing the evolution of oil vapors from such mixture of oil and adsorbent clay by the application of super-atmospheric pressure thereto, suflicient to maintain the oil substantially in the liquid phase, reducing thepressure on said heated flow stream to cause the formation of oil vapors, continuously passing such oil vapors in a. flowing stream through a, contact zone wherein the vapors are broughtinto intimate contact with the adsorbent clay, and maintaining the oil vapors and adsorbent clay at such reduced pressures for a period of time sufiicient to insure the desired contact between the clay and the oil vapors.

6. The continuous method of purifying mineral oils with adsorbents, comprising continuously heating a flow stream of mineral oil to be treated and a finely divided adsorbent clay to a temperature above that at which the oil under treatment vaporizes but below a cracking temperature, preventing the evolution of oil vapors from such mixture of oil and adsorbent clay by the application of super-atmospheric pressure thereto suflicient to maintain the oil substantially in the liquid phase, reducing the pressure on said heated flow stream to efiect the formation of oil vapors, continuously passing such oil vapors in a flowing stream through a contact zone wherein the vapors are brought into intimate contact with the adsorbent clay, maintaining the oil vapors and adsorbent clay at such reduced pressures for a period of time suflicient to insure the desired cont-act between the clay and the oil vapors, and then further reducing the pressure on the flowing stream of oil vapors and clay to permit separation of lighter and purifying fractions from heavier and undesired fractions.

7. In a method of purifying and decolorizing mineral oils, the step of subjecting a mixture of mineral oil to be decolorized and an adsorbent treating agent to a temperature above that at which the oil would normally vaporize, but below a cracking temperature, coincidentally subjecting the mixture to a' superatmospheric pressure suflicient to prevent the formation of oil vapors to cause the oil to thoroughly impregnate the adsorbent, reducing the pressure on such mixture sufliciently to cause the evolution of oil vapors, and then further reducing the pressure on the mixture of oil vapors and adsorbent to separate and separately remove the desired and undesired constitutents from the system.

In testimony whereof I aflix my signature.

RUDOLPH C. OSTERSTROM. 

